A mistake in Danish handball sparked AU researchers' protest against Olympic sex testing
In 1971, five AU researchers sent a memorandum directly to the IOC, calling the committee's practice "irresponsible and unethical." A sport historian has now documented the confrontation in a new research project.
It all started with a misundestanding.
In 1971, the Danish Handball Federation asked sport physician N.A. Sehested for help determining the sex of the Danish women's national team ahead of the World Championships. The federation mistakenly believed the players were required to undergo a chromosome test in order to compete. But when he approached the geneticists Aage Juhl Therkelsen and Gert Bruun Petersen at the Institute of Human Genetics at AU, he did not get the help he had expected. Instead, he was met with protest.
That protest, and what followed, is now documented in a new research article by Jörg Krieger, associate professor at the Department of Public Health, published at a time when the question of sex in sport is once again highly topical. On 26 March, the International Olympic Committee (IOC) announced a new policy stating that biological sex should form the basis for eligibility in the female category at the 2028 Olympics in Los Angeles.
Jörg Krieger's article, published in The International Journal of the History of Sport, shows that the scientific and ethical objections have remained the same for over 50 years — and that it was researchers in Aarhus who were among the most outspoken critics of the IOC.
"What surprised me most was the extent of the opposition already at the time. This was not simply a case of a few researchers expressing discomfort. There was a serious scientific critique, there were players and coaches who protested, and there were journalists who gave the critique a public platform," says Jörg Krieger.
The researchers protested publicly
The two geneticists did not simply refuse to help the sport physician carry out sex testing on the women's national team before the World Championships — they went straight to the press.
"The boundaries between male and female cannot be sharply drawn. The problems are very complicated and there are no absolute truths in biology and medicine," Therkelsen argued in an interview with Aarhus Stiftstidende.
Together with three AU colleagues — professor of psychiatry Erik Strömgren, geneticist Johannes Nielsen, and gynaecologist Mogens Ingerslev — Therkelsen and Petersen wrote a formal memorandum to the IOC's Medical Commission.
In it, the five researchers argued that biological sex is composed of chromosomal sex, somatic sex, and psychosocial sex, and that a single chromatin test only provides a crude picture of one of the three dimensions.
They warned of the risk of psychological harm to women with naturally occurring chromosomal variations and concluded that the use of the test was "irresponsible and unethical."
At the time, it was an unusually direct confrontation, according to the sport historian.
"It was remarkable that university researchers challenged the IOC so directly on a policy that was supposed to 'protect' women's sport. The memorandum did not simply say the procedure was uncomfortable. It challenged the scientific reasoning behind the policy," says Jörg Krieger.
The IOC rejects the criticism
The IOC's Medical Commission invited the five researchers to Lausanne.
After the meeting, the chair of the commission acknowledged that it was "practically impossible, scientifically, to define the sex of an athlete."
Yet he dismissed the researchers' objections as "purely theoretical" and said that the "practical" concerns of sport outweighed "the scientific side."
The test continued to be used for decades. It never uncovered a single male impostor, which was the very purpose it had been designed to serve. Instead, it affected women like Polish sprinter Ewa Kłobukowska, who in 1967 was disqualified and had her results struck from the record after a chromosome test revealed she had a so-called chromosomal mosaic — a naturally occurring variation that gave her no competitive advantage.
IOC's new rules for eligibility in the female category
In March, the International Olympic Committee (IOC) adopted new rules for eligibility in the female category at the Olympics. The rules apply from the 2028 Los Angeles Olympics.
Key provisions include:
- Only athletes classified by the IOC as biological females can compete in the female category.
- Transgender women are excluded from the female category.
- Eligibility must be documented through a one-time test that screens for the SRY gene, which is linked to male sex development. The test can be carried out using a blood, saliva, or cheek swab sample.
The rules have been met with both praise and criticism. Supporters argue they protect fairness in the female category in elite sport, while critics call them discriminatory and question the use of genetic sex testing.
A story found in the archives
Jörg Krieger first came across the memorandum during his PhD research around ten years ago, but only returned to the material recently.
"When I looked at the material again, I realised that this was not just a closed scientific or institutional exchange. It had been debated publicly to a much greater extent than I had initially understood," he says.
What struck him was how the opposition came from several directions at once. The geneticists provided the scientific critique, but journalist Knud Esmann from Aarhus Stiftstidende gave it a public platform, connecting the researchers' objections to the players on the women's national team.
The players themselves took a stand, and the Danish squad voted against the chromosome test, opting instead for a clinical examination. Handball player Charlotte Engelmark, who was a medical student, publicly refused to be tested — even if it cost her a place on the national team.
"It was not simply a scientific protest. It was a case where researchers, journalists, and athletes reinforced each other. That combination of voices is what made the Danish opposition so forceful," says Jörg Krieger.
A pattern that repeats itself
With the IOC's new policy from March 2026, the question of sex in sport is once again topical. More than 80 human rights and sport organisations have called on the IOC to abandon genetic sex testing, and UN human rights experts have publicly criticised the approach.
Jörg Krieger sees a clear parallel to what he found in the archives.
"Sport organisations still seek biological markers that can stabilise the female category. But the scientific debate often points in the opposite direction: toward complexity, variation, and caution. The historical case shows how sport can use science instrumentally while rejecting scientific critique when it threatens established policy," he says.
An Aarhus tradition
For Jörg Krieger, the story of the five AU researchers says something significant about the university's role.
"AU had a more significant historical role than one might expect. It shows a tradition of combining scientific rigour with public engagement," he says.
And that tradition is still alive at AU. Today, colleagues are researching the same questions, but from different angles. Some focus on sport's power structures and history, others on how the rules for women's eligibility should be designed. And it is precisely that breadth that makes the research environment strong, according to Jörg Krieger.
"The strength is not that everyone reaches the same conclusion, but that the debate is based on serious research. Universities have an important role to play when sport organisations make decisions that affect athletes' bodies, health, and rights. AU researchers were part of that conversation in the 1970s, and it remains a highly relevant field today."
The article "Testing Boundaries: Claiming Authority of Sex in Sport" by Jörg Krieger and Lindsay Parks Pieper is published in The International Journal of the History of Sport.